On 7.03.2023 17:44, Dmitry Baryshkov wrote:
> On 15/11/2022 12:11, AngeloGioacchino Del Regno wrote:
>> As specified in this driver, the context banks are 0x1000 apart but
>> on some SoCs the context number does not necessarily match this
>> logic, hence we end up using the wrong ASID: keeping in mind that
>> this IOMMU implementation relies heavily on SCM (TZ) calls, it is
>> mandatory that we communicate the right context number.
>>
>> Since this is all about how context banks are mapped in firmware,
>> which may be board dependent (as a different firmware version may
>> eventually change the expected context bank numbers), introduce a
>> new property "qcom,ctx-num": when found, the ASID will be forced
>> as read from the devicetree.
>>
>> When "qcom,ctx-num" is not found, this driver retains the previous
>> behavior as to avoid breaking older devicetrees or systems that do
>> not require forcing ASID numbers.
>>
>> Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
>> [Marijn: Rebased over next-20221111]
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
>> ---
>> drivers/iommu/arm/arm-smmu/qcom_iommu.c | 18 +++++++++++++++---
>> 1 file changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
>> index bfd7b51eb5db..491a8093f3d6 100644
>> --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
>> +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
>> @@ -551,7 +551,8 @@ static int qcom_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
>> * index into qcom_iommu->ctxs:
>> */
>> if (WARN_ON(asid < 1) ||
>> - WARN_ON(asid > qcom_iommu->num_ctxs)) {
>> + WARN_ON(asid > qcom_iommu->num_ctxs) ||
>> + WARN_ON(qcom_iommu->ctxs[asid - 1] == NULL)) {
>
> Separate change in my opinion. Please split it to a separate patch with proper Fixes: tag.
>
>> put_device(&iommu_pdev->dev);
>> return -EINVAL;
>> }
>> @@ -638,7 +639,8 @@ static int qcom_iommu_sec_ptbl_init(struct device *dev)
>> static int get_asid(const struct device_node *np)
>> {
>> - u32 reg;
>> + u32 reg, val;
>> + int asid;
>> /* read the "reg" property directly to get the relative address
>> * of the context bank, and calculate the asid from that:
>> @@ -646,7 +648,17 @@ static int get_asid(const struct device_node *np)
>> if (of_property_read_u32_index(np, "reg", 0, ®))
Use platform_get_resource(pdev, IORESOURCE_MEM, 0); reg = res->start
or something like this, the current approach relies on #address-cells = <1>
Konrad
>> return -ENODEV;
>> - return reg / 0x1000; /* context banks are 0x1000 apart */
>> + /*
>> + * Context banks are 0x1000 apart but, in some cases, the ASID
>> + * number doesn't match to this logic and needs to be passed
>> + * from the DT configuration explicitly.
>> + */
>> + if (of_property_read_u32(np, "qcom,ctx-num", &val))
>> + asid = reg / 0x1000;
>> + else
>> + asid = val;
>
> As a matter of preference (and logic) I'd have written that as:
>
> if (!of_property_read(np, "qcom,ctx-num", &val))
> asid = val;
> else
> asid = reg / 0x1000;
>
> LGTM otherwise
>
>> +
>> + return asid;
>> }
>> static int qcom_iommu_ctx_probe(struct platform_device *pdev)
>
